Graphical user interfaces and occlusion prevention for fisheye lenses with line segment foci

ABSTRACT

A method for generating a presentation of a region-of-interest in an original image for display on a display screen, comprising: establishing a lens for the region-of-interest, the lens having a magnified focal region for the region-of-interest at least partially surrounded by a shoulder region having diminishing magnification, the focal region having a perimeter defined by a radius r from a line segment; receiving one or more signals to adjust at least one of the radius r and a length len of the line segment to thereby adjust the perimeter; and, applying the lens to the original image to produce the presentation.

This application claims priority from U.S. Pat. Appl. No. 60/574,931filed on May 28, 2004, U.S. patent application Ser. No. 11/138,979 filedon May 27, 2005 and issued as U.S. Pat. No. 8,106,927, and U.S. patentapplication Ser. No. 13/343,894 filed on Jan. 5, 2012 and issued as U.S.Pat. No. 8,350,872, each of which are herein incorporated by referencein their entireties.

FIELD OF THE INVENTION

This invention relates to the field of computer graphics processing, andmore specifically, to a method and system for adjustingdetail-in-context lenses in detail-in-context presentations withgraphical user interfaces while reducing occlusion.

BACKGROUND OF THE INVENTION

Modern computer graphics systems, including virtual environment systems,are used for numerous applications such as flight training,surveillance, and even playing computer games. In general, theseapplications are launched by the computer graphics system's operatingsystem upon selection by a user from a menu or other graphical userinterface (“GUI”). A GUI is used to convey information to and receivecommands from users and generally includes a variety of GUI objects orcontrols, including icons, toolbars, drop-down menus, text, dialogboxes, buttons, and the like. A user typically interacts with a GUI byusing a pointing device (e.g., a mouse) to position a pointer or cursorover an object and “clicking” on the object.

One problem with these computer graphics systems is their inability toeffectively display detailed information for selected graphic objectswhen those objects are in the context of a larger image. A user mayrequire access to detailed information with respect to an object inorder to closely examine the object, to interact with the object, or tointerface with an external application or network through the object.For example, the detailed information may be a close-up view of theobject or a region of a digital map image.

While an application may provide a GUI for a user to access and viewdetailed information for a selected object in a larger image, in doingso, the relative location of the object in the larger image may be lostto the user. Thus, while the user may have gained access to the detailedinformation required to interact with the object, the user may losesight of the context within which that object is positioned in thelarger image. This is especially so when the user must interact with theGUI using a computer mouse or keyboard. The interaction may furtherdistract the user from the context in which the detailed information isto be understood. This problem is an example of what is often referredto as the “screen real estate problem”.

A need therefore exists for an improved method and system for adjustingdetailed views of selected information within the context of surroundinginformation presented on the display of a computer graphics system.Accordingly, a solution that addresses, at least in part, the above andother shortcomings is desired.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is provided a method forgenerating a presentation of a region-of-interest in an original imagefor display on a display screen, comprising: establishing a lens for theregion-of-interest, the lens having a magnified focal region for theregion-of-interest at least partially surrounded by a shoulder regionhaving diminishing magnification, the focal region having a perimeterdefined by a radius r from a line segment; receiving one or more signalsto adjust at least one of the radius r and a length len of the linesegment to thereby adjust the perimeter; and, applying the lens to theoriginal image to produce the presentation.

According to another aspect of the invention, there is provided a methodin a computer system for reducing occlusion in a presentation of aregion-of-interest of an original image, the presentation generated byapplying a lens to the original image, the lens having a bounds and afocal region with a magnification m for the region-of-interest at leastpartially surrounded by a shoulder region having diminishingmagnification and a width sw, the focal region having a perimeterdefined by a radius r from a line segment having a length len, themethod comprising: determining a maximum radius maxr for defining theperimeter of the focal region from a distance dl between a point nearthe bounds of the lens and a nearest point on the line segment, themagnification m, and the width sw of the shoulder region, whereinmaxr=sw/(m−1)−dl; and, restricting adjustment of the radius r to belowthe maximum radius maxr to thereby reduce occlusion of the shoulderregion by the focal region.

In accordance with further aspects of the present invention there isprovided an apparatus such as a data processing system, a method foradapting this system, as well as articles of manufacture such as acomputer readable medium having program instructions recorded thereonfor practising the method of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the embodiments of the presentinvention will become apparent from the following detailed description,taken in combination with the appended drawings, in which:

FIG. 1 is a graphical representation of the geometry for constructing athree-dimensional perspective viewing frustum, relative to an x, y, zcoordinate system, in accordance with elastic presentation spacegraphics technology;

FIG. 2 is a graphical representation of the geometry of a presentationin accordance with elastic presentation space graphics technology;

FIG. 3 is a block diagram illustrating a data processing system adaptedfor implementing an embodiment of the invention;

FIG. 4 is a partial screen capture illustrating a GUI having lenscontrol elements for user interaction with detail-in-context datapresentations in accordance with an embodiment of the invention;

FIG. 5 is a partial screen capture illustrating a GUI and lens in whichthe lens has a focal region based on a line segment source in accordancewith an embodiment of the invention;

FIG. 6 is a partial screen capture illustrating the GUI and lens of FIG.5 in which the focal region of the lens is rotated and extended inlength in accordance with an embodiment of the invention;

FIG. 7 is a partial screen capture illustrating the GUI and lens of FIG.6 in which the focal region of the lens is extended in width inaccordance with an embodiment of the invention;

FIG. 8 is a partial screen capture illustrating an alternate GUI andlens in which the lens has a focal region based on a line segment sourcein accordance with an embodiment of the invention; and,

FIG. 9 is a flow chart illustrating operations of software moduleswithin the memory of the data processing system for generating apresentation of a region-of-interest in an original image for display ona display screen in accordance with an embodiment of the invention.

It will be noted that throughout the appended drawings, like featuresare identified by like reference numerals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, numerous specific details are set forth toprovide a thorough understanding of the invention. However, it isunderstood that the invention may be practiced without these specificdetails. In other instances, well-known software, circuits, structuresand techniques have not been described or shown in detail in order notto obscure the invention. The term “data processing system” is usedherein to refer to any machine for processing data, including thecomputer systems and network arrangements described herein. The presentinvention may be implemented in any computer programming languageprovided that the operating system of the data processing systemprovides the facilities that may support the requirements of the presentinvention. Any limitations presented would be a result of a particulartype of operating system or computer programming language and would notbe a limitation of the present invention.

The “screen real estate problem” generally arises whenever large amountsof information are to be displayed on a display screen of limited size.Known tools to address this problem include panning and zooming. Whilethese tools are suitable for a large number of visual displayapplications, they become less effective where sections of the visualinformation are spatially related, such as in layered maps andthree-dimensional representations, for example. In this type ofinformation display, panning and zooming are not as effective as much ofthe context of the panned or zoomed display may be hidden.

A recent solution to this problem is the application of“detail-in-context” presentation techniques. Detail-in-context is themagnification of a particular region-of-interest (the “focal region” or“detail”) in a data presentation while preserving visibility of thesurrounding information (the “context”). This technique hasapplicability to the display of large surface area media (e.g. digitalmaps) on computer screens of variable size including graphicsworkstations, laptop computers, personal digital assistants (“PDAs”),and cell phones.

In the detail-in-context discourse, differentiation is often madebetween the terms “representation” and “presentation”. A representationis a formal system, or mapping, for specifying raw information or datathat is stored in a computer or data processing system. For example, adigital map of a city is a representation of raw data including streetnames and the relative geographic location of streets and utilities.Such a representation may be displayed visually on a computer screen orprinted on paper. On the other hand, a presentation is a spatialorganization of a given representation that is appropriate for the taskat hand. Thus, a presentation of a representation organizes such thingsas the point of view and the relative emphasis of different parts orregions of the representation. For example, a digital map of a city maybe presented with a region magnified to reveal street names.

In general, a detail-in-context presentation may be considered as adistorted view (or distortion) of a portion of the originalrepresentation or image where the distortion is the result of theapplication of a “lens” like distortion function to the originalrepresentation. A detailed review of various detail-in-contextpresentation techniques such as “Elastic Presentation Space” (“EPS”) (or“Pliable Display Technology” (“PDT”)) may be found in a publication byMarianne S. T. Carpendale, entitled “A Framework for ElasticPresentation Space” (Carpendale, Marianne S. T., A Framework for ElasticPresentation Space (Burnaby, British Columbia: Simon Fraser University,1999)), and incorporated herein by reference.

In general, detail-in-context data presentations are characterized bymagnification of areas of an image where detail is desired, incombination with compression of a restricted range of areas of theremaining information (i.e. the context), the result typically givingthe appearance of a lens having been applied to the display surface.Using the techniques described by Carpendale, points in a representationare displaced in three dimensions and a perspective projection is usedto display the points on a two-dimensional presentation display. Thus,when a lens is applied to a two-dimensional continuous surfacerepresentation, for example, the resulting presentation appears to bethree-dimensional. In other words, the lens transformation appears tohave stretched the continuous surface in a third dimension. In EPSgraphics technology, a two-dimensional visual representation is placedonto a surface; this surface is placed in three-dimensional space; thesurface, containing the representation, is viewed through perspectiveprojection; and the surface is manipulated to effect the reorganizationof image details. The presentation transformation is separated into twosteps: surface manipulation or distortion and perspective projection.

FIG. 1 is a graphical representation of the geometry 100 forconstructing a three-dimensional (“3D”) perspective viewing frustum 220,relative to an x, y, z coordinate system, in accordance with elasticpresentation space (EPS) graphics technology. In EPS technology,detail-in-context views of two-dimensional (“2D”) visual representationsare created with sight-line aligned distortions of a 2D informationpresentation surface within a 3D perspective viewing frustum 220. InEPS, magnification of regions of interest and the accompanyingcompression of the contextual region to accommodate this change in scaleare produced by the movement of regions of the surface towards theviewpoint (“VP”) 240 located at the apex of the pyramidal shape 220containing the frustum. The process of projecting these transformedlayouts via a perspective projection results in a new 2D layout whichincludes the zoomed and compressed regions. The use of the thirddimension and perspective distortion to provide magnification in EPSprovides a meaningful metaphor for the process of distorting theinformation presentation surface. The 3D manipulation of the informationpresentation surface in such a system is an intermediate step in theprocess of creating a new 2D layout of the information.

FIG. 2 is a graphical representation of the geometry 200 of apresentation in accordance with EPS graphics technology. EPS graphicstechnology employs viewer-aligned perspective projections to producedetail-in-context presentations in a reference view plane 201 which maybe viewed on a display. Undistorted 2D data points are located in abasal plane 210 of a 3D perspective viewing volume or frustum 220 whichis defined by extreme rays 221 and 222 and the basal plane 210. The VP240 is generally located above the centre point of the basal plane 210and reference view plane (“RVP”) 201. Points in the basal plane 210 aredisplaced upward onto a distorted surface 230 which is defined by ageneral 3D distortion function (i.e. a detail-in-context distortionbasis function). The direction of the perspective projectioncorresponding to the distorted surface 230 is indicated by the lineFPo-FP 231 drawn from a point FPo 232 in the basal plane 210 through thepoint FP 233 which corresponds to the focus or focal region or focalpoint of the distorted surface 230. Typically, the perspectiveprojection has a direction 231 that is viewer-aligned (i.e., the pointsFPo 232, FP 233, and VP 240 are collinear).

EPS is applicable to multidimensional data and is well suited toimplementation on a computer for dynamic detail-in-context display on anelectronic display surface such as a monitor. In the case of twodimensional data, EPS is typically characterized by magnification ofareas of an image where detail is desired 233, in combination withcompression of a restricted range of areas of the remaining information(i.e. the context) 234, the end result typically giving the appearanceof a lens 230 having been applied to the display surface. The areas ofthe lens 230 where compression occurs may be referred to as the“shoulder” 234 of the lens 230. The area of the representationtransformed by the lens may be referred to as the “lensed area”. Thelensed area thus includes the focal region and the shoulder. Toreiterate, the source image or representation to be viewed is located inthe basal plane 210. Magnification 233 and compression 234 are achievedthrough elevating elements of the source image relative to the basalplane 210, and then projecting the resultant distorted surface onto thereference view plane 201. EPS performs detail-in-context presentation ofn-dimensional data through the use of a procedure wherein the data ismapped into a region in an (n+1) dimensional space, manipulated throughperspective projections in the (n+1) dimensional space, and then finallytransformed back into n-dimensional space for presentation. EPS hasnumerous advantages over conventional zoom, pan, and scrolltechnologies, including the capability of preserving the visibility ofinformation outside 234 the local region of interest 233.

For example, and referring to FIGS. 1 and 2, in two dimensions, EPS canbe implemented through the projection of an image onto a reference plane201 in the following manner. The source image or representation islocated on a basal plane 210, and those regions of interest 233 of theimage for which magnification is desired are elevated so as to move themcloser to a reference plane situated between the reference viewpoint 240and the reference view plane 201. Magnification of the focal region 233closest to the RVP 201 varies inversely with distance from the RVP 201.As shown in FIGS. 1 and 2, compression of regions 234 outside the focalregion 233 is a function of both distance from the RVP 201, and thegradient of the function describing the vertical distance from the RVP201 with respect to horizontal distance from the focal region 233. Theresultant combination of magnification 233 and compression 234 of theimage as seen from the reference viewpoint 240 results in a lens-likeeffect similar to that of a magnifying glass applied to the image.Hence, the various functions used to vary the magnification andcompression of the source image via vertical displacement from the basalplane 210 are described as lenses, lens types, or lens functions. Lensfunctions that describe basic lens types with point and circular focalregions, as well as certain more complex lenses and advancedcapabilities such as folding, have previously been described byCarpendale.

FIG. 3 is a block diagram of a data processing system 300 adapted toimplement an embodiment of the invention. The data processing system 300is suitable for implementing EPS technology, for displayingdetail-in-context presentations of representations in conjunction with adetail-in-context graphical user interface (GUI) 400, as describedbelow, and for adjusting detail-in-context lenses in detail-in-contextpresentations while reducing occlusion. The data processing system 300includes an input device 310, a central processing unit (“CPU”) 320,memory 330, and a display 340. The input device 310 may include akeyboard, a mouse, a pen and tablet, a trackball, an eye trackingdevice, a position tracking device, or a similar device. The CPU 320 mayinclude dedicated coprocessors and memory devices. The memory 330 mayinclude RAM, ROM, databases, or disk devices. And, the display 340 mayinclude a computer screen, terminal device, or a hardcopy producingoutput device such as a printer or plotter. The data processing system300 has stored therein data representing sequences of instructions whichwhen executed cause the method described herein to be performed. Ofcourse, the data processing system 300 may contain additional softwareand hardware a description of which is not necessary for understandingthe invention.

Thus, the data processing system 300 includes computer executableprogrammed instructions for directing the system 300 to implement theembodiments of the present invention. The programmed instructions may beembodied in one or more software modules 331 resident in the memory 330of the data processing system 300. Alternatively, the programmedinstructions may be embodied on a computer readable medium (such as a CDdisk or floppy disk) which may be used for transporting the programmedinstructions to the memory 330 of the data processing system 300.Alternatively, the programmed instructions may be embedded in acomputer-readable, signal-bearing medium that is uploaded to a networkby a vendor or supplier of the programmed instructions, and thissignal-bearing medium may be downloaded through an interface to the dataprocessing system 300 from the network by end users or potential buyers.

As mentioned, detail-in-context presentations of data using techniquessuch as pliable surfaces, as described by Carpendale, are useful inpresenting large amounts of information on limited-size displaysurfaces. Detail-in-context views allow magnification of a particularregion-of-interest (the “focal region”) 233 in a data presentation whilepreserving visibility of the surrounding information 210. In thefollowing, GUIs are described having lens control elements that can beimplemented in software and applied to the editing of multi-layer imagesand to the control of detail-in-context data presentations. The softwarecan be loaded into and run by the data processing system 300 of FIG. 3.

FIG. 4 is a partial screen capture illustrating a GUI 400 having lenscontrol elements for user interaction with detail-in-context datapresentations in accordance with an embodiment of the invention.Detail-in-context data presentations are characterized by magnificationof areas of an image where detail is desired, in combination withcompression of a restricted range of areas of the remaining information(i.e. the context), the end result typically giving the appearance of alens having been applied to the display screen surface. This lens 410includes a “focal region” 420 having high magnification, a surrounding“shoulder region” 430 where information is typically visibly compressed,and a “base” 412 surrounding the shoulder region 430 and defining theextent of the lens 410. In FIG. 4, the lens 410 is shown with a circularshaped base 412 (or outline) and with a focal region 420 lying near thecenter of the lens 410. However, the lens 410 and focal region 420 mayhave any desired shape. For example, in FIG. 5, the lens 410 has anoblong shape. As mentioned above, the base of the lens 412 may becoextensive with the focal region 420.

In general, the GUI 400 has lens control elements that, in combination,provide for the interactive control of the lens 410. The effectivecontrol of the characteristics of the lens 410 by a user (i.e., dynamicinteraction with a detail-in-context lens) is advantageous. At any giventime, one or more of these lens control elements may be made visible tothe user on the display surface 340 by appearing as overlay icons on thelens 410. Interaction with each element is performed via the motion ofan input or pointing device 310 (e.g., a mouse) with the motionresulting in an appropriate change in the corresponding lenscharacteristic. As will be described, selection of which lens controlelement is actively controlled by the motion of the pointing device 310at any given time is determined by the proximity of the iconrepresenting the pointing device 310 (e.g. cursor) on the displaysurface 340 to the appropriate component of the lens 410. For example,“dragging” of the pointing device at the periphery of the boundingrectangle of the lens base 412 causes a corresponding change in the sizeof the lens 410 (i.e. “resizing”). Thus, the GUI 400 provides the userwith a visual representation of which lens control element is beingadjusted through the display of one or more corresponding icons.

For ease of understanding, the following discussion will be in thecontext of using a two-dimensional pointing device 310 that is a mouse,but it will be understood that the invention may be practiced with other2D or 3D (or even greater numbers of dimensions) pointing devicesincluding a trackball, a pen and tablet, a keyboard, an eye trackingdevice, and a position tracking device.

A mouse 310 controls the position of a cursor icon 401 that is displayedon the display screen 340. The cursor 401 is moved by moving the mouse310 over a flat surface, such as the top of a desk, in the desireddirection of movement of the cursor 401. Thus, the two-dimensionalmovement of the mouse 310 on the flat surface translates into acorresponding two-dimensional movement of the cursor 401 on the displayscreen 340.

A mouse 310 typically has one or more finger actuated control buttons(i.e. mouse buttons). While the mouse buttons can be used for differentfunctions such as selecting a menu option pointed at by the cursor 401,the disclosed invention may use a single mouse button to “select” a lens410 and to trace the movement of the cursor 401 along a desired path.Specifically, to select a lens 410, the cursor 401 is first locatedwithin the extent of the lens 410. In other words, the cursor 401 is“pointed” at the lens 410. Next, the mouse button is depressed andreleased. That is, the mouse button is “clicked”. Selection is thus apoint and click operation. To trace the movement of the cursor 401, thecursor 401 is located at the desired starting location, the mouse buttonis depressed to signal the computer 320 to activate a lens controlelement, and the mouse 310 is moved while maintaining the buttondepressed. After the desired path has been traced, the mouse button isreleased. This procedure is often referred to as “clicking” and“dragging” (i.e. a click and drag operation). It will be understood thata predetermined key on a keyboard 310 could also be used to activate amouse click or drag. In the following, the term “clicking” will refer tothe depression of a mouse button indicating a selection by the user andthe term “dragging” will refer to the subsequent motion of the mouse 310and cursor 401 without the release of the mouse button.

The GUI 400 may include the following lens control elements: move,pickup, resize base, resize focus, fold, magnify, zoom, and scoop. Eachof these lens control elements has at least one lens control icon oralternate cursor icon associated with it. In general, when a lens 410 isselected by a user through a point and click operation, the followinglens control icons may be displayed over the lens 410: pickup icon 450,base outline icon 412, base bounding rectangle icon 411, focal regionbounding rectangle icon 421, handle icons 481, 482, 491 magnify slidebar icon 440, zoom icon 495, and scoop slide bar icon 540 (see FIG. 5).Typically, these icons are displayed simultaneously after selection ofthe lens 410. In addition, when the cursor 401 is located within theextent of a selected lens 410, an alternate cursor icon 460, 470, 480,490, 495 may be displayed over the lens 410 to replace the cursor 401 ormay be displayed in combination with the cursor 401. These lens controlelements, corresponding icons, and their effects on the characteristicsof a lens 410 are described below with reference to FIGS. 4 and 5.

In general, when a lens 410 is selected by a point and click operation,bounding rectangle icons 411, 421 are displayed surrounding the base 412and focal region 420 of the selected lens 410 to indicate that the lens410 has been selected. With respect to the bounding rectangles 411, 421one might view them as glass windows enclosing the lens base 412 andfocal region 420, respectively. The bounding rectangles 411, 421 includehandle icons 481, 482, 491 allowing for direct manipulation of theenclosed base 412 and focal region 420 as will be explained below. Thus,the bounding rectangles 411, 421 not only inform the user that the lens410 has been selected, but also provide the user with indications as towhat manipulation operations might be possible for the selected lens 410though use of the displayed handles 481, 482, 491. Note that it is wellwithin the scope of the present invention to provide a bounding regionhaving a shape other than generally rectangular. Such a bounding regioncould be of any of a great number of shapes including oblong, oval,ovoid, conical, cubic, cylindrical, polyhedral, spherical, etc.

Moreover, the cursor 401 provides a visual cue indicating the nature ofan available lens control element. As such, the cursor 401 willgenerally change in form by simply pointing to a different lens controlicon 450, 412, 411, 421, 481, 482, 491, 440, 540. For example, whenresizing the base 412 of a lens 410 using a corner handle 491, thecursor 401 will change form to a resize icon 490 once it is pointed at(i.e. positioned over) the corner handle 491. The cursor 401 will remainin the form of the resize icon 490 until the cursor 401 has been movedaway from the corner handle 491.

Lateral movement of a lens 410 is provided by the move lens controlelement of the GUI 400. This functionality is accomplished by the userfirst selecting the lens 410 through a point and click operation. Then,the user points to a point within the lens 410 that is other than apoint lying on a lens control icon 450, 412, 411, 421, 481, 482, 491,440, 540. When the cursor 401 is so located, a move icon 460 isdisplayed over the lens 410 to replace the cursor 401 or may bedisplayed in combination with the cursor 401. The move icon 460 not onlyinforms the user that the lens 410 may be moved, but also provides theuser with indications as to what movement operations are possible forthe selected lens 410. For example, the move icon 460 may includearrowheads indicating up, down, left, and right motion. Next, the lens410 is moved by a click and drag operation in which the user clicks anddrags the lens 410 to the desired position on the screen 340 and thenreleases the mouse button 310. The lens 410 is locked in its newposition until a further pickup and move operation is performed.

Lateral movement of a lens 410 is also provided by the pickup lenscontrol element of the GUI. This functionality is accomplished by theuser first selecting the lens 410 through a point and click operation.As mentioned above, when the lens 410 is selected a pickup icon 450 isdisplayed over the lens 410 near the centre of the lens 410. Typically,the pickup icon 450 will be a crosshairs. In addition, a base outline412 is displayed over the lens 410 representing the base 412 of the lens410. The crosshairs 450 and lens outline 412 not only inform the userthat the lens has been selected, but also provides the user with anindication as to the pickup operation that is possible for the selectedlens 410. Next, the user points at the crosshairs 450 with the cursor401. Then, the lens outline 412 is moved by a click and drag operationin which the user clicks and drags the crosshairs 450 to the desiredposition on the screen 340 and then releases the mouse button 310. Thefull lens 410 is then moved to the new position and is locked thereuntil a further pickup operation is performed. In contrast to the moveoperation described above, with the pickup operation, it is the outline412 of the lens 410 that the user repositions rather than the full lens410.

Resizing of the base 412 (or outline) of a lens 410 is provided by theresize base lens control element of the GUI. After the lens 410 isselected, a bounding rectangle icon 411 is displayed surrounding thebase 412. For a rectangular shaped base 412, the bounding rectangle icon411 may be coextensive with the perimeter of the base 412. The boundingrectangle 411 includes handles 491. These handles 491 can be used tostretch the base 412 taller or shorter, wider or narrower, orproportionally larger or smaller. The corner handles 491 will keep theproportions the same while changing the size. The middle handles (notshown) will make the base 412 taller or shorter, wider or narrower.Resizing the base 412 by the corner handles 491 will keep the base 412in proportion. Resizing the base 412 by the middle handles will changethe proportions of the base 412. That is, the middle handles change theaspect ratio of the base 412 (i.e. the ratio between the height and thewidth of the bounding rectangle 411 of the base 412). When a user pointsat a handle 491 with the cursor 401 a resize icon 490 may be displayedover the handle 491 to replace the cursor 401 or may be displayed incombination with the cursor 401. The resize icon 490 not only informsthe user that the handle 491 may be selected, but also provides the userwith indications as to the resizing operations that are possible withthe selected handle. For example, the resize icon 490 for a cornerhandle 491 may include arrows indicating proportional resizing. Theresize icon (not shown) for a middle handle may include arrowsindicating width resizing or height resizing. After pointing at thedesired handle 491 the user would click and drag the handle 491 untilthe desired shape and size for the base 412 is reached. Once the desiredshape and size are reached, the user would release the mouse button 310.The base 412 of the lens 410 is then locked in its new size and shapeuntil a further base resize operation is performed.

Resizing of the focal region 420 of a lens 410 is provided by the resizefocus lens control element of the GUI. After the lens 410 is selected, abounding rectangle icon 421 is displayed surrounding the focal region420. For a rectangular shaped focal region 420, the bounding rectangleicon 421 may be coextensive with the perimeter of the focal region 420.The bounding rectangle 421 includes handles 481, 482. These handles 481,482 can be used to stretch the focal region 420 taller or shorter, wideror narrower, or proportionally larger or smaller. The corner handles 481will keep the proportions the same while changing the size. The middlehandles 482 will make the focal region 420 taller or shorter, wider ornarrower. Resizing the focal region 420 by the corner handles 481 willkeep the focal region 420 in proportion. Resizing the focal region 420by the middle handles 482 will change the proportions of the focalregion 420. That is, the middle handles 482 change the aspect ratio ofthe focal region 420 (i.e. the ratio between the height and the width ofthe bounding rectangle 421 of the focal region 420). When a user pointsat a handle 481, 482 with the cursor 401 a resize icon 480 may bedisplayed over the handle 481, 482 to replace the cursor 401 or may bedisplayed in combination with the cursor 401. The resize icon 480 notonly informs the user that a handle 481, 482 may be selected, but alsoprovides the user with indications as to the resizing operations thatare possible with the selected handle. For example, the resize icon 480for a corner handle 481 may include arrows indicating proportionalresizing. The resize icon 480 for a middle handle 482 may include arrowsindicating width resizing or height resizing. After pointing at thedesired handle 481, 482, the user would click and drag the handle 481,482 until the desired shape and size for the focal region 420 isreached. Once the desired shape and size are reached, the user wouldrelease the mouse button 310. The focal region 420 is then locked in itsnew size and shape until a further focus resize operation is performed.

Folding of the focal region 420 of a lens 410 is provided by the foldcontrol element of the GUI. In general, control of the degree anddirection of folding (i.e. skewing of the viewer aligned vector 231 asdescribed by Carpendale) is accomplished by a click and drag operationon a point 471, other than a handle 481, 482, on the bounding rectangle421 surrounding the focal region 420. The direction of folding isdetermined by the direction in which the point 471 is dragged. Thedegree of folding is determined by the magnitude of the translation ofthe cursor 401 during the drag. In general, the direction and degree offolding corresponds to the relative displacement of the focus 420 withrespect to the lens base 410. In other words, and referring to FIG. 2,the direction and degree of folding corresponds to the displacement ofthe point FP 233 relative to the point FPo 232, where the vector joiningthe points FPo 232 and FP 233 defines the viewer aligned vector 231. Inparticular, after the lens 410 is selected, a bounding rectangle icon421 is displayed surrounding the focal region 420. The boundingrectangle 421 includes handles 481, 482. When a user points at a point471, other than a handle 481, 482, on the bounding rectangle 421surrounding the focal region 420 with the cursor 401, a fold icon 470may be displayed over the point 471 to replace the cursor 401 or may bedisplayed in combination with the cursor 401. The fold icon 470 not onlyinforms the user that a point 471 on the bounding rectangle 421 may beselected, but also provides the user with indications as to what foldoperations are possible. For example, the fold icon 470 may includearrowheads indicating up, down, left, and right motion. By choosing apoint 471, other than a handle 481, 482, on the bounding rectangle 421 auser may control the degree and direction of folding. To control thedirection of folding, the user would click on the point 471 and drag inthe desired direction of folding. To control the degree of folding, theuser would drag to a greater or lesser degree in the desired directionof folding. Once the desired direction and degree of folding is reached,the user would release the mouse button 310. The lens 410 is then lockedwith the selected fold until a further fold operation is performed.

Magnification of the lens 410 is provided by the magnify lens controlelement of the GUI. After the lens 410 is selected, the magnify controlis presented to the user as a slide bar icon 440 near or adjacent to thelens 410 and typically to one side of the lens 410. Sliding the bar 441of the slide bar 440 results in a proportional change in themagnification of the lens 410. The slide bar 440 not only informs theuser that magnification of the lens 410 may be selected, but alsoprovides the user with an indication as to what level of magnificationis possible. The slide bar 440 includes a bar 441 that may be slid upand down, or left and right, to adjust and indicate the level ofmagnification. To control the level of magnification, the user wouldclick on the bar 441 of the slide bar 440 and drag in the direction ofdesired magnification level. Once the desired level of magnification isreached, the user would release the mouse button 310. The lens 410 isthen locked with the selected magnification until a furthermagnification operation is performed. In general, the focal region 420is an area of the lens 410 having constant magnification (i.e. if thefocal region is a plane). Again referring to FIGS. 1 and 2,magnification of the focal region 420, 233 varies inversely with thedistance from the focal region 420, 233 to the reference view plane(RVP) 201. Magnification of areas lying in the shoulder region 430 ofthe lens 410 also varies inversely with their distance from the RVP 201.Thus, magnification of areas lying in the shoulder region 430 will rangefrom unity at the base 412 to the level of magnification of the focalregion 420.

Zoom functionality is provided by the zoom lens control element of theGUI. Referring to FIG. 2, the zoom lens control element, for example,allows a user to quickly navigate to a region of interest 233 within acontinuous view of a larger presentation 210 and then zoom in to thatregion of interest 233 for detailed viewing or editing. Referring toFIG. 4, the combined presentation area covered by the focal region 420and shoulder region 430 and surrounded by the base 412 may be referredto as the “extent of the lens”. Similarly, the presentation area coveredby the focal region 420 may be referred to as the “extent of the focalregion”. The extent of the lens may be indicated to a user by a basebounding rectangle 411 when the lens 410 is selected. The extent of thelens may also be indicated by an arbitrarily shaped figure that boundsor is coincident with the perimeter of the base 412. Similarly, theextent of the focal region may be indicated by a second boundingrectangle 421 or arbitrarily shaped figure. The zoom lens controlelement allows a user to: (a) “zoom in” to the extent of the focalregion such that the extent of the focal region fills the display screen340 (i.e. “zoom to focal region extent”); (b) “zoom in” to the extent ofthe lens such that the extent of the lens fills the display screen 340(i.e. “zoom to lens extent”); or, (c) “zoom in” to the area lyingoutside of the extent of the focal region such that the area without thefocal region is magnified to the same level as the extent of the focalregion (i.e. “zoom to scale”).

In particular, after the lens 410 is selected, a bounding rectangle icon411 is displayed surrounding the base 412 and a bounding rectangle icon421 is displayed surrounding the focal region 420. Zoom functionality isaccomplished by the user first selecting the zoom icon 495 through apoint and click operation When a user selects zoom functionality, a zoomcursor icon 496 may be displayed to replace the cursor 401 or may bedisplayed in combination with the cursor 401. The zoom cursor icon 496provides the user with indications as to what zoom operations arepossible. For example, the zoom cursor icon 496 may include a magnifyingglass. By choosing a point within the extent of the focal region, withinthe extent of the lens, or without the extent of the lens, the user maycontrol the zoom function. To zoom in to the extent of the focal regionsuch that the extent of the focal region fills the display screen 340(i.e. “zoom to focal region extent”), the user would point and clickwithin the extent of the focal region. To zoom in to the extent of thelens such that the extent of the lens fills the display screen 340 (i.e.“zoom to lens extent”), the user would point and click within the extentof the lens. Or, to zoom in to the presentation area without the extentof the focal region, such that the area without the extent of the focalregion is magnified to the same level as the extent of the focal region(i.e. “zoom to scale”), the user would point and click without theextent of the lens. After the point and click operation is complete, thepresentation is locked with the selected zoom until a further zoomoperation is performed.

Alternatively, rather than choosing a point within the extent of thefocal region, within the extent of the lens, or without the extent ofthe lens to select the zoom function, a zoom function menu with multipleitems (not shown) or multiple zoom function icons (not shown) may beused for zoom function selection. The zoom function menu may bepresented as a pull-down menu. The zoom function icons may be presentedin a toolbar or adjacent to the lens 410 when the lens is selected.Individual zoom function menu items or zoom function icons may beprovided for each of the “zoom to focal region extent”, “zoom to lensextent”, and “zoom to scale” functions described above. In thisalternative, after the lens 410 is selected, a bounding rectangle icon411 may be displayed surrounding the base 412 and a bounding rectangleicon 421 may be displayed surrounding the focal region 420. Zoomfunctionality is accomplished by the user selecting a zoom function fromthe zoom function menu or via the zoom function icons using a point andclick operation. In this way, a zoom function may be selected withoutconsidering the position of the cursor 401 within the lens 410.

The concavity or “scoop” of the shoulder region 430 of the lens 410 isprovided by the scoop lens control element of the GUI. After the lens410 is selected, the scoop control is presented to the user as a slidebar icon 540 (see FIG. 5) near or adjacent to the lens 410 and typicallybelow the lens 410. Sliding the bar (not shown) of the slide bar 540results in a proportional change in the concavity or scoop of theshoulder region 430 of the lens 410. The slide bar 540 not only informsthe user that the shape of the shoulder region 430 of the lens 410 maybe selected, but also provides the user with an indication as to whatdegree of shaping is possible. The slide bar 540 includes a bar (notshown) that may be slid left and right, or up and down, to adjust andindicate the degree of scooping. To control the degree of scooping, theuser would click on the bar of the slide bar 540 and drag in thedirection of desired scooping degree. Once the desired degree ofscooping is reached, the user would release the mouse button 310. Thelens 410 is then locked with the selected scoop until a further scoopingoperation is performed.

Advantageously, a user may choose to hide one or more lens control icons450, 412, 411, 421, 481, 482, 491, 440, 495, 540 shown in FIGS. 4 and 5from view so as not to impede the user's view of the image within thelens 410. This may be helpful, for example, during an editing or moveoperation. A user may select this option through means such as a menu,toolbar, or lens property dialog box.

In addition, the GUI 400 maintains a record of control elementoperations such that the user may restore pre-operation presentations.This record of operations may be accessed by or presented to the userthrough “Undo” and “Redo” icons 497, 498, through a pull-down operationhistory menu (not shown), or through a toolbar.

Thus, detail-in-context data viewing techniques allow a user to viewmultiple levels of detail or resolution on one display 340. Theappearance of the data display or presentation is that of one or morevirtual lenses showing detail 233 within the context of a larger areaview 210. Using multiple lenses in detail-in-context data presentationsmay be used to compare two regions of interest at the same time. Foldingenhances this comparison by allowing the user to pull the regions ofinterest closer together. Moreover, using detail-in-context technologysuch as PDT, an area of interest can be magnified to pixel levelresolution, or to any level of detail available from the sourceinformation, for in-depth review. The digital images may include graphicimages, maps, photographic images, or text documents, and the sourceinformation may be in raster, vector, or text form.

For example, in order to view a selected object or area in detail, auser can define a lens 410 over the object using the GUI 400. The lens410 may be introduced to the original image to form the a presentationthrough the use of a pull-down menu selection, tool bar icon, etc. Usinglens control elements for the GUI 400, such as move, pickup, resizebase, resize focus, fold, magnify, zoom, and scoop, as described above,the user adjusts the lens 410 for detailed viewing of the object orarea. Using the magnify lens control element, for example, the user maymagnify the focal region 420 of the lens 410 to pixel quality resolutionrevealing detailed information pertaining to the selected object orarea. That is, a base image (i.e., the image outside the extent of thelens) is displayed at a low resolution while a lens image (i.e., theimage within the extent of the lens) is displayed at a resolution basedon a user selected magnification 440, 441.

In operation, the data processing system 300 employs EPS techniques withan input device 310 and GUI 400 for selecting objects or areas fordetailed display to a user on a display screen 340. Data representing anoriginal image or representation is received by the CPU 320 of the dataprocessing system 300. Using EPS techniques, the CPU 320 processes thedata in accordance with instructions received from the user via an inputdevice 310 and GUI 400 to produce a detail-in-context presentation. Thepresentation is presented to the user on a display screen 340. It willbe understood that the CPU 320 may apply a transformation to theshoulder region 430 surrounding the region-of-interest 420 to affectblending or folding in accordance with EPS technology. For example, thetransformation may map the region-of-interest 420 and/or shoulder region430 to a predefined lens surface, defined by a transformation ordistortion function and having a variety of shapes, using EPStechniques. Or, the lens 410 may be simply coextensive with theregion-of-interest 420.

The lens control elements of the GUI 400 are adjusted by the user via aninput device 310 to control the characteristics of the lens 410 in thedetail-in-context presentation. Using an input device 310 such as amouse, a user adjusts parameters of the lens 410 using icons and scrollbars of the GUI 400 that are displayed over the lens 410 on the displayscreen 340. The user may also adjust parameters of the image of the fullscene. Signals representing input device 310 movements and selectionsare transmitted to the CPU 320 of the data processing system 300 wherethey are translated into instructions for lens control.

Moreover, the lens 410 may be added to the presentation before or afterthe object or area is selected. That is, the user may first add a lens410 to a presentation or the user may move a pre-existing lens intoplace over the selected object or area. The lens 410 may be introducedto the original image to form the presentation through the use of apull-down menu selection, tool bar icon, etc.

Advantageously, by using a detail-in-context lens 410 to select anobject or area for detailed information gathering, a user can view alarge area (i.e., outside the extent of the lens 410) while focusing inon a smaller area (or within the focal region 420 of the lens 410)surrounding the selected object. This makes it possible for a user toaccurately gather detailed information without losing visibility orcontext of the portion of the original image surrounding the selectedobject.

Now, according to the present invention, improved GUIs are provided formanipulating fisheye lenses and associated representation data whilereducing occlusion.

Frequently, data presented in geographic information systems and imagescollected in remote sensing systems contains extended data features suchas roads, railways, and streams which are not necessarily aligned witheither major direction of a presentation axis pair (e.g., the x, y axis;the North, East cartographic axis; etc.). As described above, fisheyelenses 410 with adjustable shapes and sizes provide a useful means ofpresenting the details of such data features within the context of thesurrounding data. However, there is a need for an improved GUI for usewith representations having features that do not align with common axissystems. The present invention provides such a GUI and addresses issuesof data occlusion that can arise in certain instances. In particular,the present invention provides additional GUI elements and methods thatcan be used for manipulating the parameters of fisheye lenses 410. Thepresent invention is well suited to lenses 410 for which the definingshape of the focal region 420 can be represented by one line segment forsimple lens shapes, or by two or more adjoined line segments in the caseof complex lens focal region shapes.

The invention is shown schematically in FIGS. 5 through 7, in which alens 410 with a line segment focus 420 is represented, as applied to aregular grid 550. In particular, FIG. 5 is a partial screen captureillustrating a GUI 500 and lens 410 in which the lens 410 has a focalregion 420 based on a line segment source 510, 520 (i.e., a line segmentfocus 420) in accordance with an embodiment of the invention. FIG. 6 isa partial screen capture illustrating the GUI 500 and lens 410 of FIG. 5in which the focal region 420 of the lens 410 is rotated and extended inlength in accordance with an embodiment of the invention. And, FIG. 7 isa partial screen capture illustrating the GUI 500 and lens 410 of FIG. 6in which the focal region 420 of the lens 410 is extended in width inaccordance with an embodiment of the invention.

In FIGS. 5-7, the points representing the perimeter 501 of the focalregion 420 are equidistant, that is, at a distance r, from a centralline segment 510, 520 which will be referred to as the “source linesegment”. The area of the focal region 420 has uniform magnification.The perimeter 501 of the focal region 420 can be represented by twoparallel line segments 531, 541 joined by semicircles 511, 521 atopposite ends as shown in FIG. 5. In other words, the focal region 420has an oblong shape. Of course the focal region 420 could also have arectangular, oval, or other such shape. The focal region 420 is providedwith four handle icons 510, 520, 530, 540 for adjusting the size andshape of the focal region 420. A handle icon 510, 520 is located at eachend of the source line segment. In addition, a handle icon 530, 560 islocated on each parallel line segment 531, 561 of the perimeter 501.

According to the present invention, a user may use a standard inputdevice such as a mouse or other pointing device 310, and, beginning witha “click” or other indication to commence a dragging operation, drag anend 510, 520 of the source line segment to a new location. In oneembodiment of the present invention, dragging one of the source linesegment handles (e.g., 510) in a direction collinear with the sourceline segment causes a change in the length of the focal region 420,independent of the location of the other line segment end (e.g., 520).Translation of one line segment end (e.g., 510) relative to the otherend (e.g., 520) can also be used to effect a rotation of the source linesegment and hence the focal region 420. In this manner, usingtranslation of the endpoints 510, 520 as needed, the focal region 420can be extended to encompass, for example, the two endpoints of adistance measurement to display the endpoints clearly at highmagnification. In addition, a focal region 420 extended in this mannercan be used to magnify the entire path between points of interest inorder to better display objects or entities in the direct line of sightbetween the points of interest. These embodiment are shown in FIGS. 5and 6 where FIG. 5 shows the original focal region position and FIG. 6shows the adjusted focal region position (i.e., lengthened and rotated).

For the purpose of adjusting the focal region width, additional handles530, 560 may be provided on the sides 531, 561 of the focal regionperimeter 501. Click and drag operations on these handles 530, 560 causean expansion of the focal region in a direction normal to the sourceline segment (i.e., an increase in width). FIG. 7 shows a lens 410 withincreased focal region width as compared to the lens 410 shown in FIG.6.

According to another embodiment of the invention, the movement of thetwo source line segment end handles 510, 520 is coupled, such thatmovement of one end (e.g., 510) causes a corresponding movement of theother line segment end (e.g., 520) in an opposite direction.

According to another embodiment of the invention, the source linesegment length is held constant, and the motion of the lens handles 510,520 is constrained to effect only rotation of the line segment about acentral point (e.g., midway between points 510, 520) without changingthe length of the line segment.

According to another embodiment of the invention, a compound focalregion shape may be created by adjoining multiple source line segments.With such a complex focal region, handles 510, 520 can be provided ateach line segment end for the purpose of generating a lens 410 toapproximately cover an extended feature in a representation, for examplea river with multiple bends or a path on a map.

According to another embodiment of the invention, a line segment lens orcompound focal region lens 410 may be automatically constrained to fit afeature in a representation such as a river based on foreknowledge ofthe shape, size, and other parameters of the feature, or based oncomputed recognition (e.g., pattern recognition) of the parameters ofthe feature, without the need for the user to adjust the lens parametersusing the GUI 500.

According to another embodiment of the invention, a lens 410 may betraversed along a path defined by a data feature in a representationsuch as a river or valley, through the adjustment of a slider control(e.g., one similar to 440 or 540) or other GUI element positioned on thelens or as a nearby GUI element. In this case, the line segment focus orcompound focus would be re-oriented to be parallel with the portion ofthe data feature of interest.

FIG. 8 is a partial screen capture illustrating an alternate GUI 800 andlens 410 in which the lens 410 has a focal region 420 based on a linesegment source 510, 520 in accordance with an embodiment of theinvention. The GUI 800 of FIG. 8 includes four handles 810, 820, 830,860 on the bounds 412 of the lens 410. When a user clicks and drags onone of these handles 810, 820, 830, 860, the bounds 412 of the lens 410expands or contracts accordingly. That is, the width sw of the shoulderregion 430 is adjusted. All four handles 810, 820, 830, 860 perform thesame function, and clicking and dragging on any one handle (e.g., 810)will cause all four handles 810, 820, 830, 860 to be repositioned.

Now, a particular problem with fisheye lenses 410 is the possibilitythat information in the shoulder region 430 may be occluded byinformation in the focal region 420. Occlusion typically occurs at highmagnification or in areas of the presentation where the focal regionbounds 501 approaches the lens extent 412. To avoid such occlusion, whena GUI 500 is used to resize either the focal region 420 or the shoulderregion 430 (i.e., the lens drop-off width), the user has to beconstrained from making lens adjustments that will result in occlusion,or the lens extent 412 has to be adjusted to a minimum size for which noocclusion will occur. The GUI 500 can be coupled to a dynamic widthadjustment method such as that described in U.S. patent application Ser.No. 11/041,920, which is incorporated herein by reference, such that thelens extent 412 expands automatically to prevent occlusion as the sourceline segment points 510, 520 are repositioned. However one still needsto ensure that the GUI 500 is able to restrict the focus and lensparameters to ensure that occlusion cannot occur. A method for achievingthis result is described in the following in the context of a lens 410having a line segment focus 420.

First, define the identified variables as follows:

-   -   dl is the distance an interaction point is from the source line        segment 510, 520;    -   len is the length of the source line segment 510, 520;    -   m is the magnification of the lens 410;    -   r is the distance from the source line segment 510, 520 to the        focal perimeter 501 as described above (i.e., the focal radius);        and,    -   sw is the width of the shoulder 430 of the lens 410.

The interaction point is a point near the bounds 412 of the lens 410. dlis measured from the interaction point to a nearest point on the sourceline segment 510, 520 (as it exists undisplaced). sw is the width of theshoulder 430 of the lens 410. In other words, sw is the distance fromthe edge 501 of the focal region 420 to the edge 412 of the lens 410. ris the width (or radius) of the focus 420. It determines the areasurrounding the source line segment 510, 520, or other primitive, whichhas constant magnification at the level set by the lens. It thusdetermines the focal region 420 of the lens 410. For example, for asquare focus the primitive would be a point and the focal radius r wouldbe measured axially from that point. This would result in a squarearound that point which receives constant maximum magnification. In thisexample, the shoulder width sw would scribe a rounded rectangle as allthe points that are exactly sw units are measured outward from thesquare.

Now, consider the following three cases.

Case 1: A user resizes the focal radius r (e.g., by adjusting a sidehandle 530, 540). In this case, a maximum radius maxr has to be computedso that the magnified bounds 501 of the focal region 420 does not expandpast the bounds 412 of the lens 410 which would cause occlusion of data.The maximum radius maxr may be computed as follows:maxr=sw/(m−1)−dl

In the above, maxr is infinity for m=1.

Case 2: The user resizes the shoulder width (e.g., by adjusting a handle481). In this case, a minimum shoulder width minw has to be computed sothat the bounds of the lens 412 does not shrink to a point at which itis smaller than the perimeter 501 of the magnified focal region 420which would cause occlusion of data. The minimum shoulder width minw maybe computed as follows:minw=(len+r)*(m−1)

In the above, minw=0 for m=1.

Case 3: The user repositions the source line segment end points 510,520. In this case, a maximum line length maxd has to be computed so thatthe magnified bounds 501 of the focal region 420 does not expand pastthe bounds 412 of the lens 410 which would cause occlusion of data. Themaximum line length maxd may be computed as follows:maxd=sw/(m−1)−r, for m>1maxd=r+sw+len, for m≦1

The lens extent 412 can then be adjusted to satisfy the constraints onmaxr, minw, or maxd as computed for the cases above, so that noocclusion of data in the presentation results from the application ofthe lens 410 to the representation. That is, to reduce occlusion of theshoulder region by the focal region, adjustment of the radius r isrestricted to below the maximum radius maxr, adjustment of the width swof the shoulder region is restricted to above the minimum shoulder widthminw, and/or adjustment of the length len of the line segment isrestricted to below the maximum line segment length maxd.

The above described method (i.e., with respect to FIGS. 5-8) may besummarized with the aid of a flowchart. FIG. 9 is a flow chartillustrating operations 900 of software modules 331 within the memory330 of the data processing system 300 for generating a presentation of aregion-of-interest in an original image for display on a display screenin accordance with an embodiment of the invention.

At step 901, the operations 900 start.

At step 902, a lens 410 for the region-of-interest is established, thelens 410 having a magnified focal region 420 for the region-of-interestat least partially surrounded by a shoulder region 430 havingdiminishing magnification, the focal region 420 having a perimeter 501defined by a radius r from a line segment 510, 520.

At step 903, one or more signals are received to adjust at least one ofthe radius r and a length len of the line segment 510, 520 to therebyadjust the perimeter 501.

At step 904, the lens 410 is applied to the original image to producethe presentation.

At step 905, the operations 900 end.

Preferably, the step of receiving further includes receiving one or moresignals to adjust a position of an end (e.g., 510 or 520) of the linesegment 510, 520 to thereby rotate the focal region 420. Preferably, thestep of applying further includes displacing the original image onto thelens 410 to produce a displacement and perspectively projecting thedisplacement onto a plane 201 in a direction 231 aligned with aviewpoint 240 for the region-of-interest. Preferably, the method furtherincludes displaying the presentation on the display screen 340.Preferably, the lens is a surface. Preferably, the method furtherincludes receiving the one or more signals through a GUI 500 displayedover the lens 410. Preferably, the GUI 500 has means for adjusting atleast one of the radius r, the length len, and the position. Preferably,at least some of the means are icons. Preferably, the means foradjusting the length len and the position is a handle icon 510, 520positioned at an end of the line segment 510, 520. Preferably, the meansfor adjusting the radius r is a handle icon 530, 560 positioned on aside 531, 561 of the perimeter 501. Preferably, the method furtherincludes receiving the one or more signals from a pointing device 310manipulated by a user. Preferably, the pointing device 310 is at leastone of a mouse, a pen and tablet, a trackball, a keyboard, an eyetracking device, and a position tracking device. Preferably, anadjustment to a first end (e.g., 510) of the line segment 510, 520causes a corresponding adjustment to a second end (e.g., 520) of theline segment 510, 520. Preferably, the line segment 510, 520 and focalregion 420 rotate about a center point of the line segment 510, 520.Preferably, method further includes receiving one or more signalsthrough a GUI 800 displayed over the lens 410 to adjust a width sw ofthe shoulder region 430, wherein the GUI 800 has one or more handleicons 810, 820, 830, 860 positioned on a bounds 412 of the lens 410 foradjusting the width sw.

While this invention is primarily discussed as a method, a person ofordinary skill in the art will understand that the apparatus discussedabove with reference to a data processing system 300, may be programmedto enable the practice of the method of the invention. Moreover, anarticle of manufacture for use with a data processing system 300, suchas a pre-recorded storage device or other similar computer readablemedium including program instructions recorded thereon, may direct thedata processing system 300 to facilitate the practice of the method ofthe invention. It is understood that such apparatus and articles ofmanufacture also come within the scope of the invention.

In particular, the sequences of instructions which when executed causethe method described herein to be performed by the data processingsystem 300 of FIG. 3 can be contained in a data carrier productaccording to one embodiment of the invention. This data carrier productcan be loaded into and run by the data processing system 300 of FIG. 3.In addition, the sequences of instructions which when executed cause themethod described herein to be performed by the data processing system300 of FIG. 3 can be contained in a computer software product accordingto one embodiment of the invention. This computer software product canbe loaded into and run by the data processing system 300 of FIG. 3.Moreover, the sequences of instructions which when executed cause themethod described herein to be performed by the data processing system300 of FIG. 3 can be contained in an integrated circuit productincluding a coprocessor or memory according to one embodiment of theinvention. This integrated circuit product can be installed in the dataprocessing system 300 of FIG. 3.

The embodiments of the invention described above are intended to beexemplary only. The scope of the invention is therefore intended to belimited solely by the scope of the appended claims.

The invention claimed is:
 1. A method comprising: applying a lens to animage, wherein the lens includes: an extent of the lens, a focal regionhaving a magnification and a perimeter shaped according to a radiusextending from a plurality of line segments, wherein one of theplurality of line segments has a non-zero angle with respect to anotherof the plurality of line segments, and a shoulder region having a widthbetween the focal region and the extent of the lens, wherein theshoulder region provides context for the focal region with respect to aportion of the image outside of the lens by preserving visibility ofinformation surrounding the focal region.
 2. The method of claim 1,further comprising: determining at least one of: a maximum value for theradius based at least on a present value of the magnification of thefocal region, or a minimum value for the width of the shoulder regionbased at least on the present value of the magnification of the focalregion.
 3. The method of claim 1, wherein each of the plurality of linesegments is adjoined to a different one of the plurality of linesegments.
 4. The method of claim 1, wherein each of the plurality ofline segments comprises at least one handle.
 5. The method of claim 1,further comprising automatically constraining the focal region to fit afeature in the image.
 6. The method of claim 1, further comprisingautomatically constraining the plurality of line segments to fit afeature in the image.
 7. The method of claim 1, further comprising:automatically recognizing a pattern in the image; and at least one of:automatically constraining the focal region to fit the pattern, orautomatically constraining the plurality of line segments to fit thepattern.
 8. An apparatus comprising: one or more processors togetherwith one or more memories configured to: apply a lens to an image,wherein the lens includes: an extent of the lens, a focal region havinga magnification and a perimeter shaped according to a radius extendingfrom a plurality of line segments, wherein one of the plurality of linesegments has a non-zero angle with respect to another of the pluralityof line segments, and a shoulder region having a width between the focalregion and the extent of the lens, wherein the shoulder region providescontext for the focal region with respect to a portion of the imageoutside of the lens by preserving visibility of information surroundingthe focal region.
 9. The apparatus of claim 8, wherein the one or moreprocessors together with the one or more memories are further configuredto: determine at least one of: a maximum value for the radius based atleast on a present value of the magnification of the focal region, or aminimum value for the width of the shoulder region based at least on thepresent value of the magnification of the focal region.
 10. Theapparatus of claim 8, wherein each of the plurality of line segments isadjoined to a different one of the plurality of line segments.
 11. Theapparatus of claim 8, wherein each of the plurality of line segmentscomprises at least one handle.
 12. The apparatus of claim 8, wherein theone or more processors together with the one or more memories arefurther configured to automatically constrain the focal region to fit afeature in the image.
 13. The apparatus of claim 8, wherein the one ormore processors together with the one or more memories are furtherconfigured to automatically constrain the plurality of line segments tofit a feature in the image.
 14. At least one computer-readable storagedevice including a set of instructions for execution on one or moreprocessors, wherein the set of instructions comprises: applyinginstructions for applying a lens to an image, wherein the lens includes:an extent of the lens, a focal region having a magnification and aperimeter shaped according to a radius extending from a plurality ofline segments, wherein one of the plurality of line segments has anon-zero angle with respect to another of the plurality of linesegments, and a shoulder region having a width between the focal regionand the extent of the lens, wherein the shoulder region provides contextfor the focal region with respect to a portion of the image outside ofthe lens by preserving visibility of information surrounding the focalregion.
 15. The at least one computer-readable storage device of claim14, wherein the set of instructions further comprises: determinationinstructions for determining at least one of: a maximum value for theradius based at least on a present value of the magnification of thefocal region, or a minimum value for the width of the shoulder regionbased at least on the present value of the magnification of the focalregion.
 16. The at least one computer-readable storage device of claim14, wherein each of the plurality of line segments is adjoined to adifferent one of the plurality of line segments.
 17. The at least onecomputer-readable storage device of claim 14, wherein each of theplurality of line segments comprises at least one handle.
 18. The atleast one computer-readable storage device of claim 14, wherein the setof instructions further comprises constraining instructions forautomatically constraining the focal region to fit a feature in theimage.
 19. The at least one computer-readable storage device of claim14, wherein the set of instructions further comprises constraininginstructions for automatically constraining the plurality of linesegments to fit a feature in the image.
 20. The at least onecomputer-readable storage device of claim 14, wherein the set ofinstructions further comprises: recognition instructions forautomatically recognizing a pattern in the image; and at least one of:constraining instructions for automatically constraining the focalregion to fit the pattern, or constraining instructions forautomatically constraining the plurality of line segments to fit thepattern.